The field of the present invention relates to an improved automated vacuum food packaging machine which seeks to accomplish the processing steps of loading an empty food package onto a processing turret, and subsequently performing all related processing steps including the steps of imprinting the package, loading the package with the designated food product, insuring against further processing of any unfilled or improperly filled food package, drawing vacuum, injecting nitrogen and sealing the food package while under vacuum conditions to insure the purging of all air, and effecting the discharge of the package from the turret for further handling.
It will be appreciated that a variety of packaging machines are currently available with a view toward automating the package of designated food products in a plasticized food container. It has been found that food products such as meat loaves or cheese products sold as individual slices may be conveniently packaged in plasticized food pouches such as polyethylene pouches, and it has been desirable to develop machinery which will automatically handle the package thereby to minimize manual handling and resulting purification problems associated therewith.
While the present invention has specific reference to sliced meat products as the food product to be packaged in individual polyethylene pouches, nevertheless, the machine forming the subject matter of the present invention similarly has application to other food products which are intended to be individually packaged in separate containers. By way of background, food products such as meat slices or cheese slices have conveniently been packaged on flat packs formed by a flat cardboard or hard paper backboard, wherein the meat or cheese is deposited on the backboard, and the packaging machine operating to bubble pack the top portion of the packet to effect a food package suitable for sale on a mass production basis. While machines of this type have found a high degree of success, nevertheless, it has been found that purification problems have resulted with the oxygen content of the food package, which has an effect on bacterial growth and, hence, has an impact on the shelf life of the product. In addition, such packaging systems generally are constructed along a horizontal or linear pathway, with each processing station being positioned along the linear path of travel of the food package. Hence, such packaging systems generally consume a significant amount of manufacturing space, and further require the attendance of a number of workers along the linear path of the manufacturing line in order to perform various processing functions. For example, the packaging system which involves the deposition of meat or cheese slices onto a plasticized or cardboard backboard which is then bubble-packed generally is laid out along a linear pathway wherein the food package enters the line at one end, and is processed sequentially along the linear pathway of the assembly line until a completed package is discharged from the line at the other end, the package then being self-contained, purified, sealed and discharged. In addition, the sealing operation is generally accomplished on a manual basis in that it is necessary to have an operator take each individual package, insert the same on a back support, and then activate a vacuum hood which surrounds the package, gases the same, heat seals the same, and then either ejects the package from the vacuum hood or requires the operator to remove the package therefrom.
With specific reference to the vacuum hood assemblies currently available, in most instances, a vacuum hood is provided which is pivotally mounted on a support or frame, and wherein the frame or support further incorporates the gas nozzle provided to purify the product, and also supporting the heat sealing means for heat sealing the plastic covering for the food package. In most of such packaging systems, the vacuum hood is actuated to surround the support containing the food package, a vacuum is then drawn, and the table or frame which supports the food package and the vacuum hood also supports the gas nozzles for purifying the product, as well as the heat sealing bars, which are actuated to purify and heat seal after the vacuum has been established. It has been found that in such systems, an imperfectly seated vacuum hood will affect the air content of the resulting package, and if the air content is in excess of 1.5% by volume, bacterial growth is precipitated and shelf life is affected. In addition, it has been found that if the heat sealing bar does not make proper contact with the package, and the heat seal is imperfect, once again, the air content of the resulting food package will increase with time thereby resulting in a loss of shelf life of the resulting food package.
The packaging machine of the present invention is intended to accomplish various improvements, including a minimizing of manufacturing space since the machine is designed in a compact form, the reduction of labor associated with the operation of the machine since only one operator is all that is necessary to oversee the operation of one or more of the novel machines, and further, improvements have been effected to the vacuum hood assembly and the heat sealing bar assembly.
With reference to the prior patented art, various forms of improvements in packaging systems and devices of the type referred to hereinabove have had varying degrees of success. For example, in U.S. Pat. No. 3,910,009, there is shown an improved packaging machine, wherein the improvement resides in the provision of an improved vacuum station such that packages which are filled but unsealed may be loaded into a vacuum chamber to purge virtually all of the oxygen from the package, and while under the purged condition, the pouches or food packages are sealed and then automatically removed from the vacuum chamber and unloaded from the holders associated with the vacuum chamber. It will be appreciated, however, that the above-noted device merely forms one station along a linear manufacturing line, and is not part and parcel of a compact packaging machine designed to automatically accomplish all packaging functions virtually on a sequential basis. Hence, while an improved vacuum system may be disclosed, the vacuum system is not within the framework of a single machine.
Similar comments are applicable with regard to another form of a vacuum packaging apparatus disclosed in U.S. Pat. No. 3,780,489. In the invention disclosed therein, an apparatus is provided for vacuum packaging articles in flexible pouches or bags wherein the apparatus is provided with a plurality of vacuumizing nozzles and pouch sealing means. Once again, it will be observed that the invention provided in the aforementioned patent simply provides an improved vacuum station, in effect, for a package formed by a flexible bag having a product packaged therein. Once again, the invention does not form a part of a synchronized packaging machine, but rather, forms a separate station which would be positioned along the linear path of a complete manufacturing line.
Even more exemplary of the prior art type machines is U.S. Pat. No. 3,619,975 which is directed to an improved packaging machine for packaging products in a flexible wall pouch in the presence of an inert gas, and has for its object the provision of a machine which will open flat pouches, fill the same, seal the pouch in a controlled atmosphere, and advance the same to a discharge station where the pouches are released. It will be observed, however, that the improved machine contemplates a system wherein the pouches are advanced edgewise along a predetermined horizontal path and wherein the processing stations are located along the horizontal path for operating or processing the pouches. It will further be noted that the machine provided for in the U.S. Pat. No. 3,619,975 does not perform an individual bag loading function, imprinting function, food loading function, purification and sealing function, and to thereafter discharge the food package as a completed unit. In short, the device shown in the U.S. Pat. No. 3,619,975 actually relates to a machine forming a part of a manufacturing line which, in turn, consists of a number of such machines constructed to accomplish the above-noted functions.
Various other similar type packaging machines attempting to accomplish the above-noted functions are shown in the prior patented art, such as for example, U.S. Pat. No. 3,478,492 which discloses a packaging machine including a filling station, a loading station, and sealing and trimming stations, respectively. It will be noted, however, that generally, machines of the type shown in the U.S. Pat. No. 3,478,492 relate to machines of the type seeking to fill a food container with particulate matter and, therefore, do not reach the problem of inserting bulky foodstuffs into a flexible food bag. Similarly, U.S. Pat. No. 3,094,825 shows a food packaging machine for packaging irregularly sized foodstuffs such as meat products; however, it will be observed that even with the automated machinery so described in the aforementioned patent, a significant amount of handling is still required. For example, it will be noted that in order to accomplish the positioning of the package in the vacuum box, an operator is required to grasp the open end of the bag which is under the nozzle, and guide or position the bag end around the nozzle in order to insure that the proper vacuum is obtained in the food package.
Similar problems are evident with regard to the remaining prior art considered to be relevant with regard to the subject matter described herein.